检索结果-南通市图书馆

Prediction to the Efficiency of Soft Clay sample preparation with Vacuum Loading

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1998年第2期13卷 243-251页

作者： Yan, SW Fang, SZ Tianjin Univ Dept Hydraul Engn Tianjin 300072 Peoples R China

Vacuum loading has been examined as a way of preparing uniformly consolidated soft clay samples. The facility and loading procedure are described in this paper. An analytical solution to the three dimensional consolidation equation is derived for estimating the degree of consolidation of the soil sample with vacuum loading. The given example shows that the predicted degree of consolidation of a soft clay bulk with vacuum loading is close to that measured in the consolidation process.

关键词： reconstituted clay vacuum loading sample preparation 3D consolidation analytical solution

sample preparation method to improve the efficiency of high-throughput single-molecule force spectroscopy

在线全文

学校读者我要写书评

暂无评论

Biophysics Reports 2019年第4期5卷 176-183页

作者： Lei Jin Li Kou Yanan Zeng Chunguang Hu Xiaodong Hu State Key Laboratory of Precision Measuring Technology & Instruments Tianjin University Nanchang Institute for Microtechnology of Tianjin University College of Engineering and Technology Tianjin Agricultural University

Inefficient sample preparation methods hinder the performance of high-throughput single-molecule force spectroscopy(H-SMFS) for viscous damping among reactants and unstable linkage. Here, we demonstrated a sample preparation method for H-SMFS systems to achieve a higher ratio of effective target molecules per sample cell by gas-phase silanization and reactant hydrophobization. Digital holographic centrifugal force microscopy(DH-CFM) was used to verify its performance. The experimental result indicated that the DNA stretching success ratio was improved from 0.89% to 13.5%. This enhanced efficiency preparation method has potential application for force-based DNA stretching experiments and other modifying procedures.

关键词： Specific binding Digital holographic centrifugal force microscopy sample preparation High-throughput single-molecule force spectroscopy

Quantitative Analysis of Heavy Metals in Water Based on LIBS with an Automatic Device for sample preparation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2015年第8期17卷 699-703页

作者：胡丽赵南京刘文清孟德硕方丽王寅余洋马明俊 Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences

Abstract Heavy metals in water can be deposited on graphite flakes, which can be used as an enrichment method for laser-induced breakdown spectroscopy （LIBS） and is studied in this paper. The graphite samples were prepared with an automatic device, which was composed of a loading and unloading module, a quantitatively adding solution module, a rapid heating and drying module and a precise rotating module. The experimental results showed that the sample preparation methods had no significant effect on sample distribution and the LIBS signal accumulated in 20 pulses was stable and repeatable. With an increasing amount of the sample solution on the graphite flake, the peak intensity at Cu I 324.75 nm accorded with the exponential function with a correlation coefficient of 0.9963 and the background intensity remained unchanged. The limit of detection （LOD） was calculated through linear fitting of the peak intensity versus the concentration. The LOD decreased rapidly with an increasing amount of sample solution until the amount exceeded 20 mL and the correlation coefficient of exponential function fitting was 0.991. The LOD of Pb, Ni, Cd, Cr and Zn after evaporating different amounts of sample solution on the graphite flakes was measured and the variation tendency of their LOD with sample solution amounts was similar to the tendency for Cu. The experimental data and conclusions could provide a reference for automatic sample preparation and heavy metal in situ detection.

关键词： spectroscopy automatic device sample preparation multiple enrichments,quantitative analysis laser-induced breakdown spectroscopy

sample preparation of Urine samples Prior to CE-MS in Toxicological Analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Chemistry and Chemical Engineering 2011年第7期5卷 583-594页

作者： Rovini Michele Schappler Julie Kohler Isabelle Anzini Mauriziot Veuthey Jean-Luc Rudaz Serge Dipartimento Farmaco Chimico Tecnologico Universith di Siena via Aldo Moro 53100 Siena Italy School of Pharmaceutical Sciences University of Geneva Bd d ＇Yvoy 20 1211 Geneva 4 Switzerland Swiss Centre for Applied Human Toxicology University of Geneva CMU Rue Michel-Servet 1 1211 Geneva 4 Switzerland

Capillary electrophoresis （CE） coupled with mass spectrometry （MS） with a sheath liquid interface is nowadays recognized as a powerful separation technique for drugs and metabolites analysis in human urine and can be applied in numerous fields such as clinical toxicology, drug substitution monitoring, forensic sciences and antidoping. With an acidic background electrolyte containing 15 mM ammonium formate at pH 2.5 and a sheath liquid consisting in a mixture of isopropanol/water （50：50, v/v） with 0.5% formic acid, CE-ESI-MS in positive mode demonstrated excellent performance for simultaneous analysis of basic drugs of abuse and metabolites in urine （e.g. cocaine, amphetamine, morphine and phase II metabolites）. To achieve the desired level of sensitivity, two injection modes and three sample pre-treatments were evaluated. The detection of basic drugs and phase Ⅱ metabolites in diluted urine was achieved at concentrations above 1μg/mL. In order to enhance sensitivity, a sample preparation was required. A liquid-liquid extraction （LLE） was compared with solid-phase extraction. LLE was performed at alkaline pH and samples were electrokinetically injected. A chemometric approach （Doehlert design） was carried out in order to determine optimized injection parameters. Limits of detection （LOD） down to 10 ng/mL were reached with field-amplified sample injection but phase II metabolites were not extracted. Therefore, instead of LLE a SPE was performed on C 18 sorbent, and elution fraction after washing step containing phase Ⅱ metabolites was loaded on mixed-mode anion exchanger cartridges. After electrokinetic injection, this two-step SPE allowed LOD ca. 10 ng/mL for drugs and phase Ⅱ metabolites.

关键词： Capillary electrophoresis mass spectrometry sample preparation urine toxicology.

Application of EBSD technique to ultrafine grained and nanostructured materials processed by severe plastic deformation:sample preparation, parameters optimization and analysis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2012年第8期22卷 1801-1809页

作者：陈勇军 Jarle HJELEN Hans J.ROVEN 挪威科技大学材料科学与工程系特隆赫姆7491挪威

With the help of FESEM, high resolution electron backscatter diffraction can investigate the grains/subgrains as small as a few tens of nanometers with a good angular resolution （~0.5°）. Fast development of EBSD speed （up to 1100 patterns per second） contributes that the number of published articles related to EBSD has been increasing sharply year by year. This paper reviews the sample preparation, parameters optimization and analysis of EBSD technique, emphasizing on the investigation of ultrafine grained and nanostructured materials processed by severe plastic deformation （SPD）. Detailed and practical parameters of the electropolishing, silica polishing and ion milling have been summarized. It is shown that ion milling is a real universal and promising polishing method for EBSD preparation of almost all materials. There exists a maximum value of indexed points as a function of step size. The optimum step size depends on the magnification and the board resolution/electronic step size. Grains/subgrains and texture, and grain boundary structure are readily obtained by EBSD. Strain and stored energy may be analyzed by EBSD.

关键词： electron backscatter diffraction (EBSD) sample preparation parameters optimization step size severe plastic deformation (SPD)

A new sample preparation method for the determination of acyclovir by RP-HPLC:application to a drug-drug interaction study between gefitinib and acyclovir in rats

在线全文

学校读者我要写书评

暂无评论

Journal of Chinese Pharmaceutical Sciences 2021年第6期30卷 495-504页

作者： Ying Li Zhou Wen Yongling Liu Zhibing Zhao Lei Wang Zeneng Cheng Food and Pharmaceutical Engineering Institute Guiyang UniversityGuiyang 550005China School of Life Sciences Central South UniversityChangsha 410013China School of Pharmaceutical Sciences Central South UniversityChangsha 410013China

The assay of acyclovir in plasma seems to be a challenge because of its high *** our present study,a reversed-phase high-performance liquid chromatography(RP-HPLC)method for the determination of acyclovir in rat plasma was described and validated in drug-drug interaction(DDI)between gefitinib and acyclovir in *** analytes were separated with gradient elution on C18 column(4.6 mm×250 mm,5μm),and the peaks were recorded using ultraviolet detector at a wavelength of 254 *** precipitation followed by methyl tertiary butyl ether extraction was used for sample *** calibration curve was established between 0.2 and 40μg/mL(r^(2)=0.9999).The intra-and inter-day precisions were all less than 8%,and all the biases were not more than 10%.This new method was successfully applied to a DDI study between gefitinib and acyclovir in *** up-regulated the absorption of acyclovir by about three times,and our findings guided the clinical co-administration of epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)with acyclovir.

关键词： Acyclovir High-performance liquid chromatography sample preparation Absorption Drug-drug interaction

Applied Study on Magnetic Nanometer Beads in preparation of Genechip samples

在线全文

学校读者我要写书评

暂无评论

Journal of Huazhong University of Science and Technology(Medical Sciences) 2004年第1期24卷 25-27页

作者：陈慧高华方谢欣马雪梅杨渝珍 Department of Biochemistry and Molecular Biology Department of Biological Science and Biotechnology Department of Chemical Engineering Biochip Beijing National Engineering and Research Center

A protocol for enrichment and adsorption of karyocyte from whole blood by using magnetic nanometer beads as solid phase absorbents was presented. The PCR amplification could be accomplished by using the nanobeads with karyocyte as template directly and the PCR products were applied on an oligonucleotide array to do gene typing. The HLA A PCR amplification system and a small HLA A oligonucleotide microarray were applied as the platform and an experiment protocol of separating karyocyte from whole blood using the magnetic nanometer beads (Fe 2O 3) were set up. The experimental conditions were also discussed. It showed that pH level of PBS eluent, Taq enzyme quantity and fragment length of products could influent the amplification results, and the magnetic nano beads could succeed in sample preparation in microarray to provide a promising way in automatic detection and lab on a chip.

关键词： sample preparation magnetic nanometer bead lab on a chip

在线全文

学校读者我要写书评

暂无评论

GC-MS测定中的小体积样品浓缩技术

分析测试学报 2007年第z1期26卷 138-139页

作者：王立齐刚王尚军刘鸿雁张玉玲刘晓华北京市劳动保护科学研究所北京100054 大庆市环境监测中心站黑龙江大庆163000

New preparation methods for the GC-MS analytical sample are reviewed in this *** are MT,SH-MT,PMT,ME-MT,MCT,and so on mainly.

关键词： Review GC-MS sample preparation MicroTrap

Modifying current thin-film microextraction(TFME)solutions for analyzing prohibited substances:Evaluating new coatings using liquid chromatography

在线全文

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2022年第3期12卷 470-480页

作者： Łukasz Sobczak Dominika Kołodziej Krzysztof Gorynski Bioanalysis Scientific Group Faculty of PharmacyCollegium Medicum in Bydgoszcz at Nicolaus Copernicus University in Torun85-089BydgoszczPoland

For identifying and quantifying prohibited substances,solid-phase microextraction(SPME)continues to arouse interest as a sample preparation ***,the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography(HPLC)*** octadecyl(C18)and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this *** address this situation,the present study evaluated 12 HPLC-compatible coatings,including several chemistries not currently used in this *** stationary phases of SPME devices in the geometry of thin filmcoated blades were prepared by applying silica particles bonded with various functional ligands(C18,octyl,phenyl-hexyl,3-cyanopropyl,benzenesulfonic acid,and selected combinations of these),as well as unbonded silica,to a metal *** of these chemistries have not been previously used as microextraction *** 48 most commonly misused substances were selected to assess the extraction efficacy of each coating,and eight desorption solvent compositions were used to optimize the desorption *** samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass *** evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the ***,using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

关键词： sample preparation Solid-phase microextraction Thin-film microextraction Prohibited substances Drugs of abuse High-performance liquid chromatography